Vacuum-pump



3 Sheets-Sheet 1.

J. T." HAMBAY,

(No Model.)

VACUUM PUMP.

No. 400,668. Patented Apr. 2, 18,89.

INVENTOR,

N. PETERS, Photo-Lithographer, Washingifln, D. C.

& E S S E N h w Sprengel or Geissler type.

nrnivr FFICE.

JAMES T. I-IAMBAY, OF PITTSBURG, PENNSYLVANIA,

VACUUM-PUMP.

SPECIFICATION forming part of Letters Patent No. 400,668, dated April 2,1889.

Application filed August 3, 1887. Serial No. 246,024. (No model.)

To all whom it may concern:

Be it known that I, J AMES T. HAMBAY, re siding at Pittsburg, in thecounty -of Al1egheny and State of Pennsylvania, a-citizen of theUnitedStates, have invented or discovered certain new and useful Improvementsin Vacuum-Pumps, of which improvements the following is a specification.

The invention herein relates to certain im provements in apparatus forthe production of high vacuum i. a, above twenty-eight or twenty-ninebarometric inches. The highest vacuum heretofore attainable by the useof mechanical pumps was twenty-eight or twentynine barometric inches;hence it has been necessary where a higher vacuum was desired to haverecourse to mercurialv pumps of the The capacity of these types of pumpsis limited by reason of the manner in which they are constructed andoperated.

The object of the invention is to provide a mechanical or power pumphaving such a construction and arrangement of parts that a practicallyperfect or high vacuum may be produced thereby; and to this end theinvention consists in the construction, arrangement, and combination ofparts, substantially as hereinafter more fully described and claim ed.

In the accompanying drawings, forming a part of this specification,Figure 1 is a sectional elevation of my improved pump. Fig. 2 is asimilar view, on an enlarged scale, of a modification thereof. Fig. 3 isa side elevation.

- The cylinder 1 of the pump is of the ordinary construction found inexhaust-pumps, the body portion thereof being surrounded by a jacket orcasing, 2, thus forming a space for the reception of mercury or otherliquid which will exclude the air. Within the cylinder is arranged thepiston 3, having a double cupshaped packing, 4, preferably secured tothe lower end of the piston, which is operated by the rod 5, connectedto any suitable operating device, as the crank-disk 6. The lowercylinder-head is provided with a stuffing-box, 7, of any suitableconstruction, for the pistonrod, said box being surrounded by a shell,8, attached to the cylinder-head, and also provided with a stuifing-box,9. The chamber formed by the shell 8 is filled with mercury or othersuitable liquid for the exclusion of air, said shell being connected toa reservoir, 10, for the purpose of maintaining a constant supply offluid in the chamber. Y

The under side of the upper head, 11, of the cylinderis made concave, asshown, and at the apex of its concavity is inserted a hollow plug, 12,provided with a seat for the floatvalve 13. Onto the plug is screwed oneend of the pipe 14, leading to a continuously-operating exhaust-pump ofany suitable construction. The portion of the plug 12 around andadjacent to the valve 13 is filled with mercury in order to seal thejoint between the valve 13 and its seat. A suitable reservoir, 15, isconnected to the pipe 14 or its plug, for the purpose of maintaining aconstant supply of mercury at that point. The lower end of the cylinderbelow the piston is connected by a pipe, 16, to the pipe 14, leading tothe continuously-operating exhaust-pump, as above described.

The cylinder 1 is connected at a point at or near its upper end to theupper end of the valve-cylinder 17 by a port or passage, 18. At theupper end of the cylinder 17 is formed a seat for the upwardly-closingvalve 19, provided with a valve-stem, 20, which passes through theguide-plate 21, said plate also serving as a stop to limit the downwardmovement of thevalve- Within the valve-cylinder 17 is arranged a piston,22, connected by a rod, 23, to any suitable operating mechanism-in thiscase a lever, 24, operated by an eccentric, 25, on the shaft carryingthe crank-disk 6. The lower end of the cylinder 17 is providedwithastuffing-box, 26, surrounding the rod 23, and the lower end of saidcylinder is filled with mercury from a reservoir connected thereto bythe pipe 27. The portion of the cylinder 17 above the piston is alsoconnected 'to a mercury-reservoir by a pipe, 28, and the upper end ofthe cylinder is connected by the pipe IOC piston to not only fill theupper portion of the cylinder and the port 18 when the piston is at theupper limit ofits stroke, but also to cause a certain portion to enterthe plug 12, lifting the valve 13. A sutiicient quantity of mercury isalso placed in the cylinder 17 to fill the upper end of said cylinderand the pipe 29 adjacent thereto when the piston 22 is at the upperlimit of its stroke, thereby floating the valve 19 against its seat. Airis then exhausted from the cylinder 1 and the parts connected thereto bythe operation of the pump, towhich the pipe 11 is connected, the vacuumthus produced being about twenty-eight barometric inches. The vessel orvessels to be exhausted are then connected to the pipe 29, and the valve32 in the pipe 31 being opened a corresponding vacuum is produced insaid vessels. As soon as the vessels have been exhausted as far aspossible by the action of the pump connected to the pipe 14 the valve 32is closed and the valve 30 in the pipe 29 opened, thereby formingcommunication between the pump and the vessels to be exhausted.

The movements of the pistons 3 and 22 are so adjusted relatively to eachother that the piston 22 will move up ahead of the piston 1, therebyfloating the valve 1!) against its seat and tightly sealing the jointaround said valve, thereby cutting off all communication between thecylinder 1 and the vessels to be exhausted. The piston 3 is then movedupward, carrying with it the mercury placed thereon, as above stated. Asthe piston 3 approaches the upward limit of its stroke, the mercury willflow into the port or passage 18 and, filling said port, expel all airtherefrom. As the mercury rises in the cylinder, the air will be forcedpast the valve 13, and as the sides and top of the cylinder converge, asit were, to the point Where the valve 13 is located, the mercury in itsupward movement will sweep all the air before it and force such air pastthe valve 13. To insure the expulsion of all air from the cylinder, suchan amount of mercury is placed in the cylinder that a portion thereofwill be forced into the plug. As soon as the piston 23 has completed itsupward stroke, as above described, and has moved down sufficiently farto permit the mercury in the port or passage ]S to flow back into thecylinder 1, the piston 22 moves down, thereby permitting the valve 19 todrop and opening communication between the cylinder 1 and the vessels tobe exhausted, whereupon the air in said vessels and their connectionswill expand, filling the space in the cylinder 1 above the surface ofthe mercury therein.

Repeated strokes of the piston 3, as above described, will effect apractically perfect Torrieellian vacuum in the vessels to be exhaustedand the cylinder 1. All air forced into the pipe 1t is removed to anextent equal to the capacity of the continuously-operating pumpconnected to said pipe. The pressure on the under side of the pistonwhen moving downward is relieved by the pipe 1b, connecting the lowerend of the cylinder 1 and the pipe ill, as shown.

In lieu of surrounding only the body portion of the cylinder withprotecting jacket or shell 2, as shown in Fig. 1, the cylinders 1. and17 may be entirely surrounded with such a jacket, shell, or cylinder, asshown in Fig. 2, said protecting-cylinder being either connected by apipe, 32, to the pipe 14, as shown, or else filled with mercury. \Vhenthe shell or cylinder is connected to the pipe ll, an opening, 33, isformed in the lower head of the cylinder 1' to permit of the escape ofair therefrom during the downward stroke of the piston; but when theshell 2 is filled with mercury the cylinder 1 is connected to the pipe11 by the pipe 115, as above described and as indicated by dotted lines.

The strokes, as they might be called, of the Geissler and Sprengel pumpsbecome gradually slower as the vacuum becomes higher, while in my pumpthe rapidity of stroke is independent of the vacuum and the capacity ofthe pump is far in excess of that attainable in either the Geissler orSprengel pumps.

The mercury, which is raised and lowered in the cylinder 1 by theoperation of the piston 3), acts as the fluid-piston in the Geisslerform of pump, the difference between the two being that one ismechanically operated at regular intervals, whereas the other isoperated irregularly by variations of fluid -pressure.

I claim herein as my invention- 1. In an apparatus for the production ofhigh vacuums, the combination of a cylinder having a valvular connectionwith a continuously-operating exhaust-pump and with the vessel to beexhausted, a shell surrounding said cylinder and protecting the same asagainst the admission. of air, except through connection with the vesselto be exhausted, and a suitably-packed piston operating in saidcylinder, substantially as set forth.

2. In an apparatus for the production of high vacuums, the combinationof a cylinder having a valvular connection with a continuously-operatingexhaust-pump and with the vessel to be exhausted, a shell surroundingsaid cylinder and having pipe-connections with a continuously-operatingexhaust-pump, and a suitably-packed piston operating in said cylinder,substantially as set forth.

3. In an apparatus for the production of high vacuums, the combinationof a cylinder having a valved outlet, at mechanically-operatedfluid-piston, a valve-chamber connected thereto and to the vessel to beexhausted, a valve for closing the connection to the cylinder, and amechanically-operated fluid-piston for operating said valve,substantially as set forth.

4. In an apparatus for the production of high vacuums, the combinationof a cylinder, a piston operating therein, a valve-chamber IIS thecylinder and the vessel to be exhausted, and a 1nechanically-operatedfluid-piston in said cylinder, substantially as set forth.

In testimony whereof I have hereunto set my hand.

. JAMES T. HAMBAY.

WVitnesses:

DARWIN S. WoLcoiT, R. H. WHITTLESEY.

